Method for operating an internal combustion engine

Abstract

A method for operating an internal combustion engine, in particular a gas engine having at least two cylinders, includes acquiring a cylinder-specific first cylinder signal (pmax, E) from each cylinder. At least one combustion parameter (Q, Z) of the corresponding cylinder is controlled as a function of the first cylinder signal (pmax, E), and a cylinder-specific reference cylinder value (pmax′, E′) is set for the first cylinder signal (pmax, E) for each cylinder. The at least one combustion parameter (Q, Z) of the cylinder is adjusted as a function of the deviation of the first cylinder signal (pmax, E) from the reference cylinder value (pmax′, E′), and the first cylinder signal (pmax, E) tracks the reference cylinder value (pmax′, E′).

Description

BACKGROUND OF THE INVENTION[0001]The invention relates to a method for operating an internal combustion engine, in particular a gas engine, having at least two cylinders. A cylinder-specific first cylinder signal is acquired from each cylinder, and at least one combustion parameter of the corresponding cylinder is controlled as a function of the first cylinder signal.[0002]The cylinders of an internal combustion engine normally exhibit technical differences in combustion, i.e. when combustion parameters such as the quantity of fuel or the ignition point are controlled in an overall manner, the individual contributions by the cylinders to the total work carried out by the internal combustion engine are different. The term “overall control” or “overall engine control” of combustion parameters as used in the context of the invention means that all of the cylinders of an internal combustion engine are operated with the same values for the corresponding variables, i.e., for example, for ...

AI Technical Summary

Benefits of technology

The invention provides a method for operating an internal combustion engine that takes into account differences in cylinder parameters that can result in different emissions or efficiencies of the cylinders. This is done by adjusting the combustion parameters of each cylinder to achieve smoother control dynamics. The method allows for individual control of fuel quantity and ignition points for each cylinder based on its specific needs, while maintaining overall engine control and avoiding unwanted impacts on ignition points. The method also uses acylinder-specific difference value that is supplemented by an equalization value to avoid impacts on overall metered fuel quantity and emission control.

Problems solved by technology

However, those systems do not take into account the cylinder-specific differences which arise, for example, from cylinder parameters such as air charge, deposits and wear, center of combustion, or mechanical tolerances.

These, in particular, give rise to scatter in the emissions and combustion properties, which can lead to loss of efficiency.

In this regard, cylinders with lower nitrogen oxide or NOx emissions can lose more efficiency than cylinders with higher NOx emissions can gain.

Since overall—i.e. taken over the whole internal combustion engine—certain NOx limits often have to be complied with, such a spread in the NOx emissions from the individual cylinders often results in an overall loss of efficiency of the internal combustion engine due to the cylinder-specific differences in the cylinder parameters.

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